An apparatus and method for managing power of a mobile terminal that automatically switches an input of a low dropout (LDO) regulating unit are provided.
As functions of mobile terminals are being diversified, the mobile terminals require DC voltages such as 1.2V, 1.4V, 1.8V, 2.5V, 2.5V, etc.
Thus, each power management system (PMS) of the mobile terminals includes a plurality of DCDC converters and a plurality of LDO regulators.
FIG. 4 is a block diagram showing a PMS of the related art mobile terminal.
With reference to FIG. 4, the related art PMS D100 is provided power from batteries (BATT). Accordingly, DCDC converters D111 and D112 output relatively a low voltage such as 1.8V or 1.4V, while the LDO regulators D121 to D127 output a relatively high voltage such as 2.6V to 3.0V.
The DCDC converters D111 and D112 are high-priced but have high efficiency of converting voltages, while the LDO regulators D121 to D127 are low-priced but have low efficiency of converting voltages if there is much difference between inputted or outputted voltages. Thus, if there is much difference between an input voltage and output voltage, the DCDC converters D111 and D112 are used, and if there is a little difference between the input voltage and the output voltage, the LDO regulators D121 to D127 are used.
Namely, if an output voltage is low when the same input voltage is dropped, the DCDC converters D111 and D112 are used, and if the output voltage is high when the same input voltage is dropped, the LDO regulators D121 to D127 are used.
However, because the related art PMS includes the relatively smaller number of DCDC converters D111 and D112 and the relatively larger number of LDO regulators D121 to D127, if a slightly lower voltage needs to be precisely outputted, the high-priced DCDC converters should be additionally installed.